An investigation was carried out on BaZr0.80Y0.20O3 (BZY) and SrCe0.95Yb0.05O3 (SCY) heterostructures for proton-conducting oxides. The heterostructures were produced by a combinatorial approach yielding 27 different phase fractions in a single sputter deposition. The heterostructures with different phase fractions were evaluated by electrochemical impedance spectroscopy and DC 4-probe resistivity measurement to identify promising compositions for proton-conducting oxides. The findings indicated that the higher SCY fraction in heterostructures resulted in higher conductivity under a hydrogen atmosphere. The highest conductivity was measured with BZY6-SCY94 composition, while BZY12-SCY88, BZY18-SCY82, and BZY34-SCY63 exhibited slightly lower conductivities at 500 degrees C. Additionally, it was observed that the heterostructures exhibited different trends as a function of temperature. This indicated that the hetero-interface formed in these oxides does not have a linear impact on the electrochemical performance. Another finding is that the hetero-structured oxides typically exhibited conductivity higher than 10(-2) S/cm, taken as a critical threshold, at temperatures lower than 500 degrees C. The results indicated that the heterostructures produced with the methodology in the study offer remarkable total conductivities at relatively low operating temperatures. Highlights Combinatorial development of BaZr0.80Y0.20O3 and SrCe0.95Yb0.05O3 oxides. BZY6-SCY94 heterostructure exhibited the highest total conductivity at 500 degrees C. Heterostructures produced with the methodology offer remarkable conductivities.